1. Field of the Invention
The present invention relates to load control devices for controlling the amount of power delivered to an electrical load from a power source. More specifically, the present invention relates to a wall-mountable dimmer having a modular assembly to allow for easy adjustment of the aesthetic and the color of the dimmer after installation.
2. Description of the Related Art
A conventional two-wire dimmer has two terminals: a “hot” terminal for connection to an alternating-current (AC) power supply and a “dimmed hot” terminal for connection to a lighting load. Standard dimmers use one or more semiconductor switches, such as triacs or field effect transistors (FETs), to control the current delivered to the lighting load and thus to control the intensity of the light. The semiconductor switches are typically coupled between the hot and dimmed hot terminals of the dimmer.
Smart wall-mounted dimmers include a user interface typically having a plurality of buttons for receiving inputs from a user and a plurality of visual indicators for providing feedback to the user. These smart dimmers typically include a microcontroller or other processing device for providing an advanced set of control features and feedback options to the end user. An example of a smart dimmer is described in greater detail in commonly assigned U.S. Pat. No. 5,248,919, issued on Sep. 28, 1993, entitled LIGHTING CONTROL DEVICE, the entire disclosure of which is hereby incorporated by reference.
FIG. 1 is a front view of a user interface of a prior art smart dimmer switch 10 for controlling the amount of power delivered from a source of AC power to a lighting load. As shown, the dimmer switch 10 includes a faceplate 12, a bezel 14, an intensity selection actuator 16 for selecting a desired level of light intensity of a lighting load (not shown) controlled by the dimmer switch 10, and a control switch actuator 18. Actuation of the upper portion 16A of the intensity selection actuator 16 increases or raises the light intensity of the lighting load, while actuation of the lower portion 16B of the intensity selection actuator 16 decreases or lowers the light intensity. The intensity selection actuator 16 may control a rocker switch, two separate push switches, or the like. The control switch actuator 18 may control a push switch or any other suitable type of actuator and typically provides tactile and auditory feedback to a user when pressed.
The smart dimmer 10 also includes an intensity level indicator in the form of a plurality of visual indicators 20, which are illuminated by a plurality of light sources such as light-emitting diodes (LEDs) located inside the dimmer 10. The visual indicators 20 may be arranged in an array (such as a linear array as shown) representative of a range of light intensity levels of the lighting load being controlled. The intensity level of the lighting load may range from a minimum intensity level, which may be the lowest visible intensity, but which may be zero, or “full off,” to a maximum intensity level, which is typically “full on.” Light intensity level is typically expressed as a percentage of full intensity. Thus, when the lighting load is on, light intensity level may range from 1% to 100%.
However, in order to change the color of the dimmer 10, specifically, the color of the bezel 14, the intensity selection actuator 16, and the control switch actuator 18, the dimmer must be replaced with another dimmer, which has the desired color. Since the LEDs that illuminate the visual indicators 20 are located inside the dimmer 10, the prior art dimmer is typically only offered having a single choice for the color of the visual indicators. The entire dimmer must be replaced to change the color of the LEDs.
Therefore there is a need for a load control device, which allows for easy adjustment of the color of the plastics of the user interface and the color of the visual indicators after the load control device is installed.